1. Field
The present disclosure is directed to waveguide structures, and in particular, to segmented waveguide structures coupled to a resonator.
2. Related Art
Waveguide-based integrated optics in silicon provides an ideal platform for concentrating and guiding light at the nanoscale. See R. A. Soref, J. P. Lorenzo, “All-Silicon Active and Passive Guided-Wave Components For Lambda=1.3, and 1.6, MU-M,” IEEE J. Quantum Elect. 22, 873-879 (1986). The high index contrast between silicon and common cladding materials enables extremely compact waveguides with very high mode field concentrations, and allows the use of established CMOS fabrication techniques to define photonic integrated circuits. See A. S. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu, M. Paniccia, “A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor,” Nature 427, 615-618 (2004), A. Scherer, O. Painter, J. Vuckovic, M. Loncar, T. Yoshie, “Photonic crystals for confining, guiding and emitting light,” IEEE T. Nanotechnol. 1, 4-11 (2002), and A. Layadi, A. Vonsovici, R. Orobtchouk, D. Pascal, A. Koster, “Low-loss optical waveguide on standard SOI/SIMOX substrate,” Opt. Commun 146, 31-33 (1998). It has recently become possible, by using slotted waveguides to further concentrate a large fraction of the guided mode into a gap within the center of a silicon waveguide. See Q. F. Xu, V. R. Almeida, R. R. Panepucci, M. Lipson, “Guiding and Confining Light in Void Nanostructures,” Opt. Lett. 29, 1206-1211 (2004). This geometry greatly magnifies the electric field associated with the optical mode, resulting in electric fields in excess of 106 V/m for continuous-wave, sub-millitwatt optical signals.